The present invention relates to the channel control system for a loop type signal transmission channel.
As a loop type data transmission system which links up a plurality of information devices (posts) in a loop of transmission channels, there are, as described in detail later, a variety of types available.
When a fault happens somewhere in the transmission channel of this kind of the conventional system, the loop is cut off at the fault spot and the rest of the loop beyond the fault spot is retained as a sound loop. In this case, however, many inconveniences are unavoidable. For example; the transmitting function of a post which is cut off in this way totally ceases and even when the line is restored from the fault condition, the cut-off post cannot be automatically brought to normalcy and it is necessary for this purpose to issue a cut-off cancel order from a master post. Thus, installation of the master post is indispensable for the purpose of channel control and cut-off cannot be effected when a code-relay function fault which does not cause a drop in the carrier signal level occurs.